1. Field of the Invention
The present invention relates to a motorcycle brake assembly provided with a hydraulically driven front wheel brake and rear wheel brake, for relational control of the two brakes.
2. Background Art
A motorcycle brake actuation is carried out using a brake lever provided on the handlebar and a brake pedal provided on a step. Braking force is distributed to the front wheel brake and rear wheel brake according, to actuation of each of the actuating means.
In Japanese Patent Laid-open Publication No. Hei. 7-196068, for example, there is disclosed an example using partial electronic control. The brake system of this type is shown in FIG. 4.
A front wheel brake 02 and a rear wheel brake 05 are hydraulic brakes. A lever master cylinder 07 is provided on a brake lever actuating means, while a pedal master cylinder 012 is provided on a brake pedal 011.
A lever hydraulic system 08 extending from the lever master cylinder 07 is connected to the front wheel brake 02. A pedal hydraulic system 013 extending from the pedal master cylinder 012 is connected to one port of the three port type rear wheel brake 05. A hydraulic circuit 014 branching from the pedal hydraulic system 013 is connected to a secondary master cylinder 010, and the output of the secondary master cylinder 010 is connected to the other two ports of the rear wheel brake 05 through a control valve 016.
A brake switch 04, opened and closed by rotation of the other brake lever 06, is provided on the brake lever 06. A pressure sensor 041 for detecting hydraulic pressure is provided in the lever hydraulic system 08. A control unit 031 determines a hydraulic pressure to be generated at the secondary master cylinder 010 based on each of the detection signals from the brake switch 040 and the pressure sensor 041, and actuates an actuator 033 via a relay 032, so that the secondary master cylinder 010 generates the hydraulic pressure as required. These devices constitute an electronically controlled braking system.
When the brake pedal 011 is actuated independently, only the rear wheel brake 05 side is actuated disassociated from the front wheel.
When the brake lever 06 is actuated independently, or at the same time as the brake lever 011, the front wheel brake 02 is actuated by hydraulic pressure of the lever master cylinder 07, and the actuator 033 is actuated based on hydraulic pressure of the lever hydraulic system 08 to generate necessary hydraulic pressure in the secondary master cylinder 010 so that the rear wheel brake is actuated by the control valve 016.
The pedal hydraulic system 013 branches into two sections, with pipes leading to the rear wheel brake 05 and to the secondary master cylinder 010, and the control valve 016 is located between the secondary master cylinder 010 and the rear wheel brake 05. Therefore, the structure has many components and is complicated, and the operation of installing the piping and also maintenance can not be carried out easily.
The layout of the piping is also subject to restrictions, and there is little degree of freedom in the design.
Output from the electronically controlled actuator 33 interferes with the pedal hydraulic pressure of the secondary master cylinder, and is mechanically provided in a control valve 016 arranged downstream of the master cylinder 010, which means that the degree of freedom of electronic control is restrictive.
The present invention has been conceived in view of the above described problems. The object of the invention is to provide a brake assembly for a motorcycle that does not cause interference between hydraulic systems, allows free and independent electronic control, and which can reduce the number of components and the number of assembly steps.
In order to achieve the above described object, the present invention provides a brake assembly for a motorcycle provided with a hydraulically actuated front brake and rear brake for a front wheel and a rear wheel, respectively, including a first brake actuating means and second brake actuating means for supplying hydraulic pressure to the front and rear brakes; and an electronically controlled braking system, having a first hydraulic system extending from the first brake actuating means connected to the front brake, a second hydraulic system extending from the second brake actuating means connected to the rear brake, being input with detection values for each of a first actuation amount detection means for detecting actuation amount of the first brake actuating means and a second actuation amount detection means for detecting actuation amount of the second brake actuating means and subjecting them to computation, and outputting control signals to a hydraulically controlled actuator based on the result of computation, and actuating the front brake or the rear brake using the hydraulically controlled actuator.
If the first brake actuating means is actuated, the front wheel brake is actuated via the first hydraulic system and the actuating amount is detected by the first actuating amount detection means and output to the electronic control means. If the second brake actuating means is actuated, the rear wheel brake is actuated via the second hydraulic system, and the actuating amount is detected by the second actuating amount detecting means and output to the electronic control means.
The electronic control means carries out computation based on the inputted detected values of the actuating amount, outputs control signals to a hydraulic control actuator, and the front wheel brake and rear wheel brake are actuated in accordance with these control signals.
Piping for a hydraulic system without a control valve can be simplified and made short, the number of components can be reduced, and the piping and maintenance operations can be simplified.
The electronically controlled braking system is independent from the first and second hydraulic systems handling the hydraulic pressure, which means that no interference occurs between the two hydraulic pressures, and freedom with respect to electronic control is increased.
A second aspect of the present invention is a brake assembly of the first aspect in which the first brake actuating means is a lever master cylinder, the second brake actuating means is a pedal master cylinder, and the hydraulically controlled actuator actuates the rear brake.
The first hydraulic system is connected between the lever master cylinder and the front wheel brake, while the second hydraulic system is connected between the pedal master cylinder and the rear wheel brake. This means that the piping can be made short, and since actuation of the rear wheel brake is controlled by two systems, namely the second hydraulic system and the electronically controlled braking system, even if one of the systems fails, the brake can still be actuated the other system.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.